Freezer not freezing · symptom guide
Sub-Zero freezer not freezing in Mountain View
When the freezer goes soft but the fresh-food side still feels cold, you are almost always looking at the freezer circuit on its own — not the whole machine. Most Sub-Zero built-ins run two evaporators so each zone holds its own temperature, which means a warm freezer usually points to that zone’s evaporator fan, defrost heater, thermistor or a frost-blocked coil. We isolate the freezer circuit, prove the fault, and repair it with genuine OEM parts. The $89 service call is waived with the repair and labor is backed for 365 days.
- Freezer warm while the fridge stays cold — diagnosed by zone
- Defrost heater, thermistor, evaporator fan and damper testing
- $89 waived with repair · genuine OEM parts
$89 service call, waived with repair · 365-day warranty on all labor
Why one zone fails while the other is fine
A Sub-Zero built-in is really two cooling systems sharing a cabinet. Many models use a dual-evaporator design: the fresh-food zone and the freezer zone each have their own evaporator and airflow, so the controls can hold them at very different temperatures. When you see soft ice cream, a partially frozen drawer, frost only on one wall, or thawing along the door while the refrigerator side is unbothered, the problem lives in the freezer circuit alone.
The usual culprits are the freezer evaporator fan that has slowed or seized, a defrost heater or thermistor that lets the coil pack with ice until air can no longer move through it, or a damper that won’t feed the zone. On single-evaporator models the same complaint can point further upstream to a sealed-system or main-airflow fault — which is why we confirm which architecture your unit uses before we quote.
Symptom guide
Freezer symptom → likely cause → what we do
A quick map of the most common warm-freezer patterns on Sub-Zero built-ins and columns.
| Symptom | Likely cause | What we do |
|---|---|---|
| Soft ice cream, fridge still cold | Freezer evaporator fan or defrost | Test the freezer circuit fan and defrost cycle |
| Frost on one wall, warm elsewhere | Defrost heater / thermistor | Check the defrost components and clear the coil |
| Whole freezer column warm | That column’s fan or sealed system | Isolate and test the affected column only |
| Garage / extra freezer slowly warming | Iced evaporator from hard duty | Inspect defrost and airflow on the supplemental unit |
| Both fridge and freezer warming | Shared airflow or sealed system | Move to a full not-cooling / sealed-system diagnosis |
Confirming dual- vs single-evaporator first prevents over-diagnosis.
Before we arrive
Safe checks you can do
A few quick checks help us arrive prepared.
- Confirm the freezer set point hasn’t been changed and the controls aren’t in showroom mode.
- Make sure the freezer door and any drawers close fully against the gasket.
- Note whether the fridge side is genuinely still cold, or also drifting.
- Check for heavy frost on a single wall versus an even, light coat.
- Find your model and serial so we can confirm dual- or single-evaporator.
Two-minute check
A quick check before you call
- 01
Test the fridge side
Confirm the fresh-food zone is genuinely still cold — that points to a freezer-only fault rather than a whole-system one.
- 02
Listen for the freezer fan
With the freezer door switch held, a missing or stuttering fan sound suggests the evaporator fan or an iced coil.
- 03
Inspect the frost
Even, light frost is normal; a thick block on one wall or a bare coil with thawing points to a defrost fault.
- 04
Note the pattern
Soft, slowly thawing, or fully warm — tell us which, with your model and serial, and book a visit.
The Mountain View units we see this on
In the estate kitchens of Cuesta Park and Waverly Park, separate refrigerator and freezer columns are common, and a warm freezer column with a perfectly cold fridge column is a textbook single-zone fault — often the column’s own evaporator fan or defrost circuit. We can service the affected column without disturbing the one that’s working.
We also see plenty of supplemental and garage freezer columns tucked into Eichler additions and converted carports around Monta Loma and Whisman. Those run harder in an uninsulated space and tend to ice their evaporator faster, so a defrost fault shows up as a slowly warming freezer well before the main kitchen unit ever complains.
How a warm freezer is different from “not cooling”
It’s worth separating this from a unit that isn’t cooling at all. If the whole cabinet is drifting warm, the cause is more likely shared — condenser airflow, the compressor or the sealed system — and that’s a different page and a different test. A freezer that won’t freeze while the fridge holds cold is the signature of a zone-specific failure, and chasing it as a whole-system problem leads to replacing parts that were never at fault.
What the repair looks like
We read your model and serial, confirm whether the unit is dual- or single-evaporator, then test the freezer circuit: fan operation, the defrost heater and thermistor, the damper, and the frost pattern on the coil. You get an itemized quote before any work. Fan, thermistor and defrost-component repairs are usually quick once diagnosed, all with genuine OEM parts and a 365-day labor warranty.
Pricing
Typical freezer-repair ranges
| Repair | Draft range |
|---|---|
| Freezer evaporator fan motor | $300–$650 |
| Defrost heater | $300–$620 |
| Defrost thermistor / sensor | $240–$480 |
| Damper / air control | $280–$560 |
| Sealed system (single-evap models) | $1,450–$3,600 + parts |
Draft ranges only; the $89 service call is waived with the repair.
Reviews
What Mountain View homeowners say
Our freezer column went soft while the fridge column stayed perfectly cold. They isolated the warm column, found the evaporator fan, and replaced it with an OEM part without ever touching the working side. Clear, precise work.
Garage freezer kept slowly warming. They explained it was icing the coil from hard duty out there, fixed the defrost heater, and it’s held solid since. Honest about why it happened, not just what to replace.
Soft ice cream but the fridge was fine, so they tested the freezer circuit specifically — turned out to be the defrost thermistor. Quick, fair, and a full year of labor warranty. Saved me from a needless big repair.
FAQ
Frequently asked questions
My Sub-Zero freezer isn’t freezing but the fridge is cold — what’s wrong?
On a dual-evaporator built-in that points to the freezer circuit itself: a failing evaporator fan, a defrost heater or thermistor letting the coil ice over, or a stuck damper. We confirm the unit’s design and test that circuit rather than the whole machine.
What’s the difference between this and “not cooling”?
A warm freezer with a cold fridge is a zone-specific fault. A whole cabinet drifting warm is usually a shared cause — condenser airflow, compressor or sealed system — which we diagnose differently. Telling them apart up front avoids unnecessary parts.
Why does my garage freezer column ice up faster?
Supplemental and garage columns in Eichler additions and converted carports run harder in an uninsulated space, so the evaporator ices sooner. A defrost fault there shows as a slowly warming freezer before the main kitchen unit struggles.
Is heavy frost normal?
A light, even coat is normal. A thick block on one wall, or a bare coil with thawing, signals a defrost fault — the heater or thermistor isn’t clearing the coil so air can’t move through it.
Can you service just the affected column?
Yes. Separate refrigerator and freezer columns each have their own circuit, so we isolate and repair the warm one without disturbing the column that’s working.
How much will it cost?
Most freezer-zone repairs run from about $240 for a thermistor to $650 for an evaporator fan. Sealed-system work on single-evaporator models is higher. You get an itemized quote on-site and the $89 is waived with the repair.
Freezer soft but the fridge still cold?
Book online or call — we’ll isolate the freezer circuit and fix the real fault this week.
$89 service call, waived with repair · 365-day warranty on all labor